Cassette clamp mechanism

ABSTRACT

A surgical cassette clamping system includes a mounting plate having a first side and a second side. A bracket system may be disposed adjacent the first side of the mounting plate. A clamp motor may be disposed adjacent the mounting plate and fixed relative to the mounting plate. The clamp motor may be operably connected to the bracket system to displace the bracket system relative to the mounting plate. The system may also include a plurality of pivot arms pivotably connected to the bracket system and extending adjacent the second side of the mounting plate. An engagement portion may be attached to each of the plurality of pivot arms that cooperatively engages the second side of the mounting plate, the engagement portion being operable to pivot the pivot arms when the bracket system moves relative to the mounting plate.

PRIORITY CLAIM

This application:

-   -   (a) is a continuation application of U.S. patent application        Ser. No. 14/076,418 titled “Cassette Clamp Mechanism” which was        filed Nov. 11, 2013 whose inventors are Vincent A. Baxter and        Daniel J. Wilson which is hereby incorporated by reference in        its entirety as though fully and completely set forth herein,        and    -   (b) claims the benefit of priority of U.S. Provisional        Application Ser. No. 61/740,530 (U.S. patent application Ser.        No. 14/076,418 claimed the benefit of priority of provisional        application Ser. No. 61/740,530 titled “Cassette Clamp        Mechanism” filed on Dec. 21, 2012, whose inventors are        Vincent A. Baxter and Daniel J. Wilson), which is also hereby        incorporated by reference in its entirety as though fully and        completely set forth herein.

BACKGROUND

The devices, systems, and methods disclosed herein relate generally tocassette clamping mechanisms, and more particularly, to cassetteclamping mechanisms used on surgical consoles.

Some surgical consoles receive single-use, replaceable elements, such asfluid cassettes. Accordingly, a new cassette may be associated with theconsole for each surgery performed. Since each surgical cassette isindividually introduced onto the console, the alignment of the cassetteon the console may deviate, albeit slightly, from cassette to cassette.In macro applications, this may not be noticeable, however, in somemicro-surgical applications, these deviations can be undesirable. Inorder to provide precise and predictable control from cassette tocassette, particularly when small fluid flow differentials can impactthe surgical environment, the cassette should be precisely locatedwithin the console with some degree of precision.

The present disclosure is directed to devices, systems, and methods thataddress one or more of the disadvantages of the prior art.

SUMMARY

In an exemplary aspect, the present disclosure is directed to a surgicalcassette clamping system that includes a mounting plate having a firstside and a second side. A bracket system may be disposed adjacent thefirst side of the mounting plate. The bracket system may include atleast four connectors configured to engage the surgical cassette in adistributed manner to apply an evenly distributed clamping force on thesurgical cassette. A clamp motor may be disposed adjacent the mountingplate and fixed relative to the mounting plate. The clamp motor may beoperably connected to the bracket system to displace the bracket systemrelative to the mounting plate. The system may also include a pluralityof pivot arms pivotably connected to the bracket system and extendingadjacent the second side of the mounting plate. An engagement portionmay be attached to each of the plurality of pivot arms thatcooperatively engages the second side of the mounting plate, theengagement portion being operable to pivot the pivot arms when thebracket system moves relative to the mounting plate.

In an aspect, the bracket system comprises a first bracket and a secondbracket each formed from sheet metal. In another aspect, the systemincludes a first sensor configured to detect the presence of thesurgical cassette and includes a second sensor configured to monitor aposition of a drive wheel driven by the clamp motor.

In an aspect, the system includes a spring extending between one of theplurality of pivot arms and the bracket system. The spring may connectto the bracket system at a first connecting location and may connect tothe pivot arm at a second connecting location, the first connectinglocation and the second connecting location being located so that thespring force increases as the moment arm decreases to maintain arelatively consistent clamping force over a pivot range of about 10degrees with the spring in continuous tension. In an aspect, arelatively consistent clamping force is a clamping force that deviatesless than about 10% over the pivot range of about 10 degrees. In anaspect, the bracket system comprises a motion bracket and a clampbracket, the clamp bracket comprising the fastening element and themotion bracket comprising the second connecting location.

In an aspect, the engagement portion is a roller configured to rollalong a ramp on the mounting plate.

In another exemplary aspect, the present disclosure is directed to asurgical cassette clamping system including a bracket system comprisinga fastening element configured to engage the surgical cassette; a pivotarm pivotably connected to the bracket system at a pivot location; and aspring extending between the pivot arm and the bracket system. Thespring may connect to the bracket system at a first connecting locationand connect to the pivot arm at a second connecting location, the firstconnecting location and the second connecting location being located sothat the spring force increases as the moment arm decreases to maintaina relatively consistent clamping force over a pivot range of about 10degrees with the spring in continuous tension.

In an aspect, the pivot arm comprises a roller spaced from the pivotlocation. In an aspect the system includes a ramp disposed relative tothe roller, the ramp displacing the bracket system in a direction toclamp the surgical cassette with the fastening elements, the rampforcing the pivot arm to pivot about the pivot location as the bracketsystem displaces.

In another exemplary aspect the present disclosure is directed to amethod including receiving a surgical cassette on an orientation elementconfigured to orient the surgical cassette for clamping in a surgicalconsole; detecting the presence of the surgical cassette with a firstsensor; engaging the surgical cassette with a plurality of fasteningelements disposed adjacent corners of the surgical cassette to evenlydistribute a clamping force and move the fastening elements in a firstdirection; and fixing the surgical cassette in place by moving thefastening elements in a second direction.

In an aspect, receiving a surgical cassette on an orientation elementcomprises receiving the surgical cassette on a plurality of projectingshelf pins shaped to correspond to features of the surgical cassette. Inan aspect, engaging the surgical cassette further comprises engaging thesurgical cassette with six fastening elements with a substantially equalclamping force on each fastening element. In an aspect, fixing thesurgical cassette in place by moving the fastening elements in a seconddirection includes driving a bracket system along a ramp. In an aspect,the method includes maintaining the surgical cassette on the consolewith a plurality of retaining arms that engage a perimeter of thesurgical cassette.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory innature and are intended to provide an understanding of the presentdisclosure without limiting the scope of the present disclosure. In thatregard, additional aspects, features, and advantages of the presentdisclosure will be apparent to one skilled in the art from the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate embodiments of the devices andmethods disclosed herein and together with the description, serve toexplain the principles of the present disclosure.

FIG. 1 illustrates a perspective view of an exemplary surgical consoleaccording to one embodiment consistent with the principles of thepresent disclosure.

FIG. 2 is an illustration of an exemplary cassette clamp systemaccording to an aspect consistent with the principles of the presentdisclosure.

FIG. 3 is an illustration of an exemplary cassette clamp system in apartially exploded configuration according to an aspect consistent withthe principles of the present disclosure.

FIG. 4 is an illustration of an exemplary cassette clamp system with abezel removed according to an aspect consistent with the principles ofthe present disclosure.

FIG. 5 is an illustration of an exemplary clamp bracket assembly of thecassette clamp system of FIG. 2 according to an aspect consistent withthe principles of the present disclosure.

FIG. 6 is an illustration of another view of the exemplary clamp bracketassembly of FIG. 5 according to an aspect consistent with the principlesof the present disclosure.

FIG. 7 is an illustration of an exemplary cassette clamp system havingthe bezel and the clamp bracket removed according to an aspectconsistent with the principles of the present disclosure.

FIG. 8 is an illustration of an exemplary clamping arrangement with avariable moment arm according to an aspect consistent with theprinciples of the present disclosure.

FIG. 9 is an illustration of an exemplary cassette release arrangementin an exploded view according to an aspect consistent with theprinciples of the present disclosure.

FIG. 10 is an illustration of the exemplary cassette release arrangementof FIG. 9 from another angle according to an aspect consistent with theprinciples of the present disclosure.

FIG. 11 is an illustration of the exemplary cassette release arrangementof FIG. 9 according to an aspect consistent with the principles of thepresent disclosure.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the disclosure is intended. Any alterations and furthermodifications to the described systems, devices, and methods, and anyfurther application of the principles of the present disclosure arefully contemplated as would normally occur to one skilled in the art towhich the disclosure relates. In particular, it is fully contemplatedthat the systems, devices, and/or methods described with respect to oneembodiment may be combined with the features, components, and/or stepsdescribed with respect to other embodiments of the present disclosure.For the sake of brevity, however, the numerous iterations of thesecombinations will not be described separately. For simplicity, in someinstances the same reference numbers are used throughout the drawings torefer to the same or like parts.

The devices, systems, and methods described herein consistently andsecurely attach a replaceable cassette with a surgical console. They arearranged, in some exemplary aspects, to securely hold the cassette inplace with relatively little deviation from cassette to cassette. Inembodiments disclosed, this may allow aspiration and irrigation pressuresensors to obtain precise pressure measurements during actuation of thefluidic pump and valves during cataract surgery.

In addition, the systems, devices, and methods, permit a surgeon orother health care provider to easily attach the cassette to the consoleand to easily remove the cassette. The systems are configured in atleast some aspects to provide a relatively evenly distributed clampingforce on the cassette from top to bottom and side to side, providingincreased predictability and repeatability. In additional aspects, thesystem utilizes spring compensating moment arms to provide a moreconsistent clamping force over a larger range of clamping distances withreduced dependence on tight tolerances. As they displace, these springcompensating moment arms maintain a relatively effective moment forceacting on the cassette by compensating for increases in spring forceoccurring as a result of spring extension.

Furthermore, components of the systems may be relatively easily removedand replaced as desired, permitting relatively easy assembly, removal,and repair. For example, the clamp mechanism utilizes a clamp bracketsubassembly which assembles very easily to the module—pinch the topclamp levers, pull forward, and lift up. Removal is just as simple.Further, the clamp may be produced with relatively inexpensivefabrication methods utilizing, for example, sheet metal instead ofmachining. This results in lower manufacturing costs that can be passedon to the customer so that hospitals and clinics can more easilyincrease their capabilities and stock their surgical supplies. Inaddition, the arrangement of the clamp mechanism allows the clamp motorand other components to mount directly to a face plate. That is, in someaspects, the face plate can be machined from the front and back and doesnot require machining from the sides. That is, some aspects have noholes or taps on the side edges. In some aspects, the clamp facilitatesuse of a bezel which sheds fluid to the outside of the console. Inaddition, the bezel may utilize snapping tabs for ease of assembly orremoval. This may help prevent water ingress. Further, in some aspects,the clamp mechanism has a relatively small footprint, allowing the widthof the console to be more compact than in prior designs.

FIG. 1 illustrates an exemplary emulsification surgical console,generally designated 100. The console 100 includes a base housing 102with a computer unit 103 and an associated display screen 104 showingdata relating to system operation and performance during anemulsification surgical procedure. The console 100 also includes anumber of systems that are used together to perform the emulsificationsurgical procedures. For example, the systems include a foot pedalsystem 106 including, for example, a foot pedal 108, a fluidics system110 including a fluidics cassette 112 with a single flow control pumpthat both irrigates and aspirates the eye through flexible tubing 114,and an ultrasonic generator system including an ultrasonic oscillationhandpiece 118 with a cutting needle. These systems overlap and cooperateto perform various aspects of a cataract surgical procedure.

FIG. 2 illustrates a cassette clamp system 150 forming a part of thefluidics system 110, and FIG. 3 shows the cassette clamp system 150 in apartially exploded condition. The cassette clamp system 150 isconfigured to receive and secure a fluid cassette used to carryirrigation fluids and aspiration fluids to or from the surgical site.

Referring to both FIGS. 2 and 3, the cassette clamp system 150 includesa plastic bezel 152, a clamp bracket assembly 154, a faceplate 156, anda motor and pump assembly 158.

The exemplary bezel 152 is, in this exemplary aspect, a plastic framestructure having a receiving portion 160 configured to receive the fluidcassette and configured to protect and cover the components behind it,such as the clamp bracket assembly 154. In this embodiment, thereceiving portion 160 is rectangular shaped and includes a plurality ofslots, openings, and cut-outs that provide access to portions of theclamp bracket assembly 154 and other components and elements of thecassette clamp system 150, while providing an aesthetic, cleanappearance. Along a periphery of the receiving portion 160, the bezel152 accommodates an ejection button 162 forming a part of a cassetterelease arrangement. This ejection button 162 is disposed at a locationjust above the receiving portion 160 and is located so that a user maypress the button with a finger or thumb while catching or accessing theejecting fluid cassette with other fingers of the same hand.Accordingly, the button 162 is disposed in a location that promotes andenables simple ejection and removal of a fluid cassette from the console100. The bezel 152 may reduce fluid ingress into the console 100 and thecassette clamp system 150. It may shed fluid to the outside of theconsole 100. In one embodiment, the bezel 152 utilizes snapping tabs toconnect to the console 100 for ease of assembly and removal. Thesesnapping tabs, in some embodiments, are disposed along the peripheraledges and fit into mating receiving holes formed in the body of theconsole 100. Accordingly, the bezel may be introduced and snapped intothe place as the tabs fit into the holes in the body of the console.Other connection features are also contemplated.

FIG. 4 shows the cassette clamp system 150 with the bezel removed and aview of the clamp bracket assembly 154 in place relative to thefaceplate 156 and the motor and pump assembly 158. FIGS. 5-7 show thecassette clamp assembly 150 independent of other components of thecassette clamp system 150. The cassette clamp assembly 150 is configuredto engage the fluid cassette, and draw it into its proper location forconsistent, predictable operation.

Referring to FIGS. 4-7, the clamp bracket assembly 154 includes a motionbracket 170, a clamp bracket 172, a plurality of pivot arms 174, and aplurality of biasing elements, shown in this exemplary embodiment asclamping springs 176 and connector springs 178.

The motion bracket 170 is disposed adjacent the bezel 152 and acts as aconnector to which other components of the clamp bracket assembly 154connect. The motion bracket 170 includes a cutout central region 180that provides access to other components of the cassette clamp system150, including components of the faceplate 156 and the motor and pumpassembly 158. The cutout central region 180 in this embodiment isrectangular shaped so that the motion bracket 170 forms a frame, throughwhich the other components may be accessed and may operate.

The motion bracket 170 is formed of sheet metal and, therefore, is bentand cut to have particular features that enable smooth and properoperation. In this example, it includes a frame 179 and sides 181 withbiasing member connections 182 formed of a slot 402 and connector hole404 in the frame 179 through which the clamping springs 176 extend toconnect the motion bracket 170 and the clamp bracket 172. It alsoincludes a long guide pin slots 184 disposed at opposing corners thatare used to limit the movement. This will be discussed further below.

Tabs 186 and rollers 188 carried on the tabs 186 provide a smoothrelative movement along parallel planes of the motion bracket 170 andthe clamp bracket 172. In this embodiment, the rollers 188 are securedto the motion bracket 170 and sized to engage the clamp bracket 172through the cutouts formed by the tabs. These rollers 188 space thesurface of the clamp bracket 172 away from the surface of the motionbracket 170 so that they do not have surface to surface contact as theymove relative to each other.

In this exemplary embodiment, the motion bracket 170 includes a motionslot 190 that is disposed transverse to the direction of movement (inthis example, the direction of movement is in the vertical direction).The motion slot 190 is configured to receive a motion pin that literallyraises and lowers the motion bracket 170. A cut-out 406 in the clampbracket (seen in FIG. 6) permits the pin (to be discussed below) toextend from the faceplate 156 to the motion bracket 170. In thisexample, an additional reinforcement element 192 provides a smooth andsupporting surface for the interface with the motion pin.

The clamp bracket 172 is configured to be carried by the motion bracket170, but also moves independently of the motion bracket 170. The clampbracket 172, like the motion bracket 170 is formed of sheet metal. Itcomprises a flat plate forming a frame 198, with a central opening 200.Lateral sides 202 of the clamp bracket 172 are bent at 90-degree anglesto project through the central cutout 180 of the motion bracket 170 inthe direction of the bevel 152. These sides 202 include a plurality offastening elements shown as tangs 204 formed therein that are sized andconfigured to engage and secure the fluid cassette. These tangs 204extend out through the openings and cutouts in the bezel 152 to engagethe fluid cassette. The fluid cassette likewise has features thatcorrespond to and engage with the tangs 204.

Like the motion bracket 170, the clamp bracket 172 includes a guide pinslot 206 and a biasing member connection 208. The guide pin slot 206aligns with the guide pin slot 184 of the motion bracket 170. The guidepin slot 206 however has a length smaller than that of the guide pinslot 184 so that when the clamp bracket assembly 154 moves relative to aguide pin in the guide pin slots 184, 206, the travel distance of themotion bracket 170 is greater than the travel distance of the clampbracket 172. This occurs because the end of the short guide pin slot 206engages and interferes with the guide pin, thereby providing amechanical stop.

The biasing member connection 208 is formed as a cutout within the frame198 and is aligned with the biasing member connection 182. In thisexample, it is sized to receive the clamping spring 176.

The clamping spring 176 is disposed within the biasing memberconnections 182, 208 and one end connects to the motion bracket 170 andthe other end connects to the clamp bracket 172 in a manner that biasesthe clamp bracket 172 to a neutral position. This clamping spring 176therefore, maintains the motion bracket 170 and the clamp bracket 172 ina position relative to each other so that the clamp bracket 172 moveswith the motion bracket 170. However, when the clamp bracket 172 guidepin slot 206 engages the guide pin, the clamp bracket motion isprevented, while the motion bracket 170 may continue to move. Thisintroduces tension into the clamping spring 176, and further movement isagainst the force of the clamping spring 176. It should be noted thatother biasing arrangements are contemplated, including coil springs,elastomeric bumpers, leaf springs, and other types of springs andbiasing systems.

The sides 181 of the motion bracket 170 include pivot connectors 210that connect the pivot arms 174 to the motion bracket 170. The pivotarms 174 include a motion stop 212, a connector end 214, and a grabpoint 216. The motion stop 212 extends from a side of the pivot arm 174and is disposed proximate the pivot connector 210. The motion stop 212prevents over rotation of the pivot arm 174 by mechanically engaging anedge of the sides 181. The connector end 214 extends in a directionsubstantially opposite that of the tangs 204. These ends 214 are formedto connect with the connector springs 178. The grab point 216 extendsfrom the pivot connector 210 and is used primarily during the assemblyprocess.

In addition, the pivot arms 174 carry engagement portions as rollers 218configured to engage with and travel along a portion of the faceplate156 as will be described below. Connectors attach the motion bracket 170to the clamp bracket 172 and prevent inadvertent disassembly of theclamp bracket assembly 154. The connectors extend through a slot in themotion bracket 170 and are fixed in place relative to the clamp bracket172.

The connector springs 178 extend from the connector end 214 of the pivotarms 174 to the side 181 and bias the pivot arms to a position that willbe described below.

FIG. 7 shows the cassette clamp system 150 with the bezel 152 and theclamp bracket assembly 154 removed. Accordingly, the faceplate 156 canbe easily seen in FIG. 7. The faceplate 156 includes a number ofconnecting elements that help secure the fluid cassette in place on theconsole 100. The face plate 156 includes a relatively projecting centralface 230, and a relatively recessed perimeter 232. The central face 230is configured to project through the central openings 180, 200 in themotion bracket 170 and the clamp bracket 172.

The central face 230 includes a recessed portion configured to receivefeatures of the fluid cassette, enabling the fluid cassette to engagefeatures of the motor and pump assembly 158. For example, the centralface 230 includes a valve drive recess 234 and a pump head recess orpassage 236. The fluid cassette is shaped to have a projecting featurethat projects into the valve drive recess 234. It can then engage and bedriven by valve drives 238 that project from the motor and pump assembly158. The valve drive recess 234 also includes an optical opening 240,shown here as a laterally extending opening. Through the optical opening240, cameras, such as, for example, as optical pressure sensors, detectdiaphragm movement on the fluid cassette to monitor pressures and/orflow through the fluid cassette. In addition, in some embodiments, theoptical opening 240 is configured to use laser detection to determinewhen a fluid cassette is seated in the cassette clamp system 150. In theabsence of a fluid cassette being detected through the optical opening240, the motor and pump assembly 158 will not operate to pump even ifsuch a command is provided by an input at the console 100.

As can be seen the pump head recess or passage 236 is configured toalign and provide access to the pump head 242 of the motor and pumpassembly 158. The pump head 242 is configured to engage against anddrive fluid through the fluid cassette when the fluid cassette isengaged with the cassette clamp system 150. The pump head 242 includes aplurality of rollers 244 radially extending from a central hub 246.

The central face 230 also includes a plurality of projecting featuresconfigured to engage or align with the fluid cassette or the clampbracket assembly 154. For example, the central face 230 includes anorientation element shown as shelf pins 260 used to orient a fluidcassette, landing pads 262 against which the fluid cassette may bepulled, and alignment pins 264 used to ensure the fluid cassette isproperly positioned. The orientation element, the landing pads 262, andthe alignment pins 264 project outwardly through receiving passages inthe bezel 152 as shown in FIG. 2 to engage a fluid cassette. In thisembodiment, the orientation element comprises two projecting shelf pins260. These shelf pins 260 are spaced apart a distance to correspond withspaced receiving notches on the fluid cassette itself. While two shelfpins 260 are shown, any number of shelf pins may be used. Furthermore,the orientation element may be any number of alternative elements thatmay assist in orienting and aligning the fluid cassette.

The perimeter face 232 of the faceplate 156 is recessed relative to thecentral face 230 and disposed behind the clamp bracket assembly 154 whenthe cassette clamp system 150 is an assembled condition. The perimeterface 232 includes a plurality of features and projections that interfacewith the clamp bracket assembly 154 and the fluid cassette to secure thefluid cassette in place on the console 100. For example, the perimeterface 232 includes projecting guide pins 280 and spring cups 282 thatextend outwardly from the perimeter face 232.

The projecting guide pins 280 are sized to extend into the guide pinslots 184, 206 on the motion bracket 170 and the clamp bracket 172. Inthis embodiment however, they do not extend through the bezel 152. Inthe exemplary embodiment shown, the spring cups 282 are distributed inthe general area of the four corners of the face plate and push againstthe clamp bracket to bias the clamp bracket to an outward position.

The perimeter face 232 also includes a through slot 284 thereinproviding a passage to the motor and pump assembly 158. Retaining arms286 pass through these slots 284 and are configured to engage a topperimeter of the fluid cassette to maintain the fluid cassette in placeon the cassette clamp system 150.

The retaining arms 286 comprise a roller 287 at their distal end that issized and configured to roll over an edge of the fluid cassette,pivotably displacing the retaining arms 286, until the roller seatswithin an indentation in the perimeter edge of the fluid cassette.Biasing members, shown as springs 288, bias the retaining arms 286 tothe position shown, which is the neutral position and the clampedposition.

Some embodiments include a sensor 289 associated with one or moreretaining arms 286 that detects the position of the retaining arms 286to identify whether a fluid cassette is present in the cassette clampsystem 150. For example, some embodiments include an optical sensor thatis configured to monitor a portion of the retaining arm 286 to detectwhen the arm 286 is displaced from its neutral position and to detectwhen the arm 286 is in a position that indicates it is seated in an edgeof a fluid cassette. The sensor may communicate with a controller thatsets a flag preventing operation of the cassette clamp system 150 untilthe sensor detects that a fluid cassette is present and properly seated.In one embodiment, the sensor detects the presence of a portion of theretaining arm 286 at a particular portion. While an optical sensor isused in some embodiments, other embodiments employ other types ofsensors, including rotary sensors, piezoelectric sensors, or othertransducers that can be used to detect positions and orientations todeduce the presence of the fluid cassette.

Opposite the perimeter face 232, the exemplary faceplate 156 includes abackside having tapered ramps 290 extending between a low region 292 (asdefined by the thickness of the faceplate 156) to a high region 294.These ramps 290 cooperate with the rollers 218 on the pivot arms 174 onthe motion bracket 170 so that as the clamp bracket assembly 154displaces vertically (or in the y direction), the rollers 218 ride alongthe ramp 290, thereby causing the clamp bracket assembly 154 tosimultaneously displace toward the perimeter face 232 and the motor andpump assembly 158 (the z direction). In some embodiments, thesimultaneous directional displacement occurs only for the motion bracket170, while the clamp bracket 172 moves in the y direction and is stoppedby a guide pin prior to being pulled in the z direction as the motionbracket 170 continues to move. As it does this, the tangs 204 of theclamp bracket 172 pull the fluid cassette in the z direction, causingthe fluid cassette to seat in the cassette clamp system 150.

Still referring to FIG. 7, the perimeter face 232 also includes aclamping cutout 298 that accommodates a clamping driving assembly 300.The clamping driving assembly 300 includes a clamp motor 302 forming apart of the motor and pump assembly 158, a drive wheel 304, and anoptical sensor 306.

The drive wheel 304 is associated with a drive shaft of the clamp motor302, either directly or indirectly, such as through a gear box.Accordingly, the clamp motor 302 may rotate the drive wheel 304 about arotation axis. The drive wheel 304 includes a projecting drive pin 308extending in a direction substantially parallel to the rotation axis;however, the projecting drive pin 308 is offset from the rotation axis.Accordingly, rotation of the drive wheel 304 by the drive motor 302results in the drive pin 308 travelling in an arcing direction. In theembodiments shown, the drive wheel 304 travels from a position where thedrive pin 308 is disposed directly below the rotation axis, or at a 6o'clock position to a 12 o'clock position, where the drive pin 308 isdisposed directly above the rotation axis. Other positions are alsocontemplated. In the embodiment shown, the drive wheel 304 engagesmotion limiting stops 307 that mechanically limit the rotation of thedrive wheel 304. Accordingly, the drive wheel 304 may rotate between thestops 307 and may rotate until the stops 307 are engaged.

The drive pin 308 is sized and shaped to extend into the slot of motionslot 190 of the motion bracket 170 (FIG. 5). Accordingly, as the drivewheel 304 rotates and the drive pin 308 correspondingly travels in anarc, the vertical displacement (or the movement in the y direction) ofthe drive pin 308 results in a corresponding vertical displacement ofthe clamp bracket assembly 154. The length of the motion slot 190 in thetransverse or x-direction permits lateral travel within the slot 190 sothat the while drive pin 308 travels in an arc, the clamp bracketassembly 154 moves only in the vertical direction, along they-direction.

The optical sensor 306 is disposed adjacent the drive wheel 304 and isconfigured to detect the position of the drive wheel 304. Accordingly,it may be used to sense when the drive wheel 304 is in a fully lockedposition, indicating that the fluid cassette is secured in the consoleand detect when the drive wheel 304 is in a fully unlocked position.Other types of position sensors are also contemplated, includingdisplacement sensors, encoders, and others.

The motor and pump assembly 158 includes the clamp motor 302, a pumpmotor 318, a valve drive motor 320 and a pump 322 connected by a motormounting plate 324. In some embodiments, the motor and pump assembly 158also includes the optical pressure sensors detecting pressures throughthe optical opening 240 and a controller shown as a PCB (Printed CircuitBoard) 330 fixed to the optical pressure sensors.

In operation, a user, such as a health care provider, can attach a fluidcassette to the console by introducing the fluid cassette to thecassette clamp system 150. To do this, the user may rest the fluidcassette on the orientation element formed of the shelf pins 260. Thefluid cassette body itself may have a perimeter shaped to accommodatethe orientation element. With one edge (e.g., the bottom edge) of thefluid cassette resting on the orientation element, the opposing edge(e.g., the upper edge) may be pivoted toward the retaining arms 286. Theretaining arms 286 are disposed so that the rollers 287 mechanicallyinterfere with the opposing edge (e.g., upper edge) of the fluidcassette as it is introduced into the cassette clamp system 150. As thefluid cassette advances, the rollers 287 displace and roll over theleading edge of the fluid cassette causing the retaining arms 286 topivot as they accommodate the displacement. This displacement is againstthe biasing force of springs 288. Accordingly, when the rollers 287reach the seats formed in the edge of the fluid cassette, the rollerssnap into place in the seats, and the retaining arms 286 retain thefluid cassette in place on the cassette clamp system. In someembodiments, the rollers 287 may extend and snap onto the face of thecassette instead of snap into seats in the cassette periphery. In yetother embodiments, instead of rollers, the retaining arms 286 includefastening elements as hooks or other fasteners.

As explained above, a sensor 289 may be used to track displacement orthe location of one or more of the retaining arms 286 as a check toconfirm when the retaining arm 286 is properly located, indicating thatthe retaining arm is correctly engaged with the fluid cassette and thatthe fluid cassette is properly positioned. In this example, the sensormay be an optical sensor, although other types of sensors also may beused.

Likewise, a sensor disposed behind the optical opening 240 may alsodetect whether the fluid cassette is properly positioned. This sensormay be a proximity sensor that detects when an object, such as the fluidcassette is disposed in front of the optical opening 240. This sensorcould be any of a plurality of different types of sensors. Furthermore,this sensor may be arranged in any of a number of other arrangements todetect when a fluid cassette is being positioned within the cassetteclamp system 150. Furthermore, although the two sensors disclosed hereinprovide a level of redundancy, other embodiments use only a singlesensor, while other embodiments use additional sensors.

The sensors communicate with a controller (shown as PCB 330) on theconsole 100 that operates to control a part of or the complete fluidicssystem 110. When the controller receives signals from the sensors thatthe fluid cassette is in place, the controller may control the clampmotor 302 to secure the fluids module in place.

In some embodiments, the controller may operate under its own initiativewhen the sensors detect the presence of the fluid cassette, while inother embodiments, the user must initiate the clamping process using aninput control, such as pressing a button, turning a dial, operating thefoot pedal, or otherwise inputting a command.

The clamp motor 302 operates by rotating the drive wheel 304 to move thedrive pin 308 from a first position corresponding to an unclampedposition to a second position corresponding to a clamped position. Theunclamped position in this embodiment is when the drive pin 308 isrelatively vertically lower than the clamped position, which in thisembodiment is when the drive pin 308 is relatively higher. Since thedrive pin 308 extends into the motion slot 190 in the motion bracket170, a change in elevation of the drive pin 308 results in acorresponding change in elevation of the motion bracket 170. Since themotion bracket 170 is constrained against side-to-side or transversemovement in the x-direction, the motion bracket 170 can only move in theup or down direction as a result of the drive pin movement.

As described above, the clamp bracket 172 is biasedly connected to themotion bracket 170 by the clamping springs 176. Therefore, as the motionbracket 170 moves in the y-direction, so does the clamp bracket 172.That is, they move together.

Referring to FIG. 4, the guide pins 280 extend through the guide pinslot 184 in the motion bracket 170 and the guide pin slot 206 in theclamp bracket 172. These guide pins 280 constrain the movement of theclamp bracket assembly 154 and prevent lateral movement in thex-direction. For a short distance, the motion bracket 170 and the clampbracket 172 move upwardly together as carried by the drive pin 308.During this upward movement, the tangs 204 of the clamp bracket 172 hookor otherwise move to a position that mechanically prevents removal ofthe fluid cassette. After the short movement in the y-direction, thebottom end of the guide pin slots 206 of the clamp bracket 172 contactthe guide pins 280, and the guide pins 280 prevent further upwardmovement of the clamp bracket 172. However, since the guide pin slots184 on the motion bracket 170 are longer than the guide pin slots 206 onthe clamp bracket 172, the motion bracket 170 may continue to move inthe y-direction. Since the motion bracket 170 continues to move upward,but the clamp bracket 172 is prevented from moving upward, the biasingforce of the clamping spring 176 is overcome and the clamping spring 176is further extended.

During the period of time discussed above where both the motion bracket170 and the clamp bracket 172 move in the y-direction together, therollers 218 on the pivot arms 174 are disposed substantially on the lowregion 292 on the backside of the faceplate 156 (FIG. 7). As the motionbracket 170 moves in the y-direction however, the rollers 218 roll upthe ramp 290. As this occurs, the entire clamp bracket assembly 154moves in the z-direction, pulling the tangs 204 against the fluidcassette and pulling the fluid cassette in the z-direction until itengages or abuts against the landing pads 262. It's worth noting that asthe clamp bracket assembly 154 moves in the z-direction, it is actingagainst the biasing force of the spring cups 282, which bias the clampbracket assembly 154 away from the perimeter face 232 of the faceplate156. In some embodiments, the motion bracket 170 may move upward untilthe rollers 218 reach the high region 294 on the backside of thefaceplate 156. In other embodiments, the y-axis travel of the motionbracket 170 stops with the rollers 218 on the ramp 290 before they reachthe high region 294. Accordingly, when securing the fluid cassette, thetangs 204 may first move upward and then move inward.

When the fluid cassette abuts against the landing pads 262, the fluidcassette cannot move further in the z-direction. As such, the clampingbracket 172 and the motion bracket 170 cannot move further in thez-direction. However, because the rollers 218 are disposed on pivotarms, the rollers 218 may continue to roll up the ramp 290 as the pivotarms 174 pivot against the force of the connector springs 178. That is,while the motion bracket 170 cannot move in the z-direction, the rollers218 may move in the z-direction by forcing the pivot arms 174 to pivotabout the pivot connectors 210. This occurs since the rollers 218 areoffset from the pivot connectors 210. As the pivot arms 174 rotatehowever, the connector springs 178 are stretched further, increasing theclamping load or holding force on the clamp bracket 172 and the fluidcassette.

The sensor 306 may detect whether the drive wheel 304 is in a positionindicative of a fully clamped condition. Accordingly, until the drivewheel 304 is fully rotated to a clamped position, the controller may notpermit further use of the fluidics module. However, if the sensor 306communicates with the controller that the drive wheel 304 is in aposition indicating that the fluid cassette is fully clamped, and thesensors at the optical opening 240 and at the retaining arm 286 indicatethat the fluid cassette is properly seated, then the controller maypermit further operation of the fluidics system 110. With the fluidcassette secured in the cassette clamp system 150, the fluidics system110 can monitor flow through the fluid cassette using the opticalsensors, and flow may be controlled using the foot pedal, another inputdevice, or simply through control programming.

The cassette clamp system 150 is set up to operate in reverse to permitremoval of the fluid cassette. In this embodiment, pressing the ejectionbutton 162 activates the controller to run the clamp motor 302 in theopposite direction, rotating the drive wheel 304 from the clampedposition to the unclamped position, and displacing the clamp bracketassembly 154 in the manner described above to loosen and permit removalof the fluid cassette.

Some embodiments of the present disclosure are arranged to provide arelatively consistent clamping force on the fluid cassette despitedifferences in fluid cassette thickness. That is, even though the clampbracket 172 may displace in the z-direction a distance that varies fromfluid cassette to fluid cassette, the clamping force remainssubstantially the same. This occurs because the clamp bracket assembly150 employs a variable moment arm. This consistency in clamping forceresults in increased consistency in cassette position and cassetteoperation.

Fluid cassettes that have differing thickness can result in the fluidcassette engaging or abutting against the landing pads 262 at when theclamp bracket 172 is at different positions in the z-direction. As such,the clamp bracket 172 with its tangs 204 may travel in the z-direction agreater distance with one fluid cassette than with another fluidcassette. In some of the embodiments described above, this variation intravel in the z-direction results in variation in the degree of pivotingby the pivot arm 174. In this embodiment, the connector springs 178connect to the motion bracket 170 and the end of the pivot arms 174 atlocations that result in a relatively consistent clamping force despitedifferences in displacement in the z-direction. It does this because thelength of the moment arm (distance of a line segment perpendicular tothe connector spring 178 and through the pivot point defined by thepivot connector 210) decreases as the spring 178 lengthens. Therefore,as the spring force increases by virtue of the extending spring 178, thelength of the moment arm correspondingly decreases. In this example, thespring 178 and the connection locations of the spring 178 on the motionbracket 170 and on the pivot arm 174 are selected so that the clampingforce is relatively consistent even when the amount of rotation of thepivot arm 174 changes.

The operation of this is shown in FIG. 8 in the context of the clampbracket 172, the pivot arms 174, and the spring 178. Accordingly, in theexample in FIG. 8, the spring 178 is selected with a spring constant ofabout 2.9 lb/in. (pounds/inch), a free spring length of about 2.0 in,and an initial tension of 0.60 lb. The mechanism geometry providesmechanical advantage of about 4 to 1 for spring to clamping force withclamping moment arm of about 0.325 in and variable moment arm for thespring of about 1.30 in at position 1. For an arm rotation of about 9.6degrees between positions 0 and 1, and another 9.6 degrees betweenpositions 1 and 2, the mechanism geometry establishes the variablemoment arm length to be about 1.42 in at position 0, 1.30 in at position1, and 1.18 in at position 2, corresponding to a stretched spring lengthof about 3.07 in at position 0, 3.30 in at position 1, and 3.51 in atposition 2, so that the resulting clamping force per arm at is about16.2 lb at position 0, 17.48 lb at position 1, and 17.87 lb at position2. This is a change of only 2.23% between position 1 and 2. This is animprovement over a system that uses a near constant moment arm of 1.30in, as the resulting force would change by about 14.1%, from 17.48 lb to20.00 lb per arm between position 1 and 2. The effect of the variablemoment arm in this example is to reduce the effective spring constant bya factor of 6.4 from 2.9 lb/in to about 0.45 lb/in between positions 1and 2. In this example, the difference between position 1 and position 2is the equivalent of the cassette thickness variance of about 0.054 in.

In another similar example, the spring 178 is selected with a springconstant of about 3.10 lb/in, a free spring length of about 1.88 in, andan initial tension of about 1.00 lb. Using the same mechanical geometryas the above example, the resulting clamping forces per arm are 20.51 lbat position 0, 21.61 lb at position 1, and 21.75 at position 2, a changeof only 6.05% for an equivalent cassette thickness variance of about0.104 in from position 0 to position 2. Or a change of only 0.65% fromposition 1 to position 2 which is an equivalent cassette thicknessvariance of about 0.054 in. The effect of the variable moment arm inthis example is to reduce the effective spring constant by a factor of19.2 from 3.1 lb/in to about 0.161 lb/in from position 1 to position 2.

As used herein, a relatively consistent clamping force is intended toinclude clamping force variations of less than about 10% whenthicknesses differ by about 0.05 in. In some embodiments, it includesclamping force variations of less than about 5%, while in otherembodiments it includes clamping force variations of less than about 3%when thicknesses differ by about 0.05 in.

FIGS. 9-11 show details of a cassette release arrangement 400 that maybe employed to release the cassette or initiate a release of thecassette from the console.

In this embodiment, the cassette release arrangement 400 permits a userto (a) release the cassette using a powered approach where the clampmotor 302 (FIG. 7) rotates the drive wheel 304 (FIG. 7) from the clampedposition to the unclamped position to release and permit removal of thefluid cassette, and also permits a user to (b) mechanically release thecassette without the use of power to operate the clamp motor. As such,even after the system is off or unplugged, a fluidics cassette may stillbe manually ejected in order to prepare the system for use in asubsequent surgery. Therefore, the user need not reboot or power thesystem for the sole purpose of removing the fluid cassette.

In the exemplary embodiment shown in FIGS. 9-11, the cassette releasearrangement 400 connects to the bezel 152 and includes a support portion402, a rotating insert 404, a sensor 406 such as an optical sensor, andthe button 162 including a button body 408 and a button cover 410. Inthe assembled condition shown in FIG. 11, a biasing element 412 extendsbetween and connects the support portion 402 and the rotating insert404, and biases the rotating insert 404 to a secured position.

The support portion 402 connects via fasteners, such as screws 416, tothe bezel 152. It includes an extension spring arm 418, a central knob420, and a clearance slot 422 that receives a part of the rotatinginsert 404. Since it connects to the bezel 152, the support portion 402is substantially fixed in place, and the various components of thecassette release arrangement move relative to the support portion 402.

The rotating insert 404 includes a central bore 430 extending through aboss 431, an extension spring arm 432, a finger portion 434, and a flagportion 436. The central bore 430 receives the central knob 420 and therotating insert 404 pivots about the central knob 420. The fingerportion 434 protrudes through the clearance slot 422. As shown in FIG.10, the finger portion 434 includes a driving surface 438 that isconfigured to engage the drive pin 308 extending into the motion slot190 of the motion bracket 170 (FIG. 5). The flag portion 436 is arrangedto be disposed adjacent the sensor 406.

The boss 431 is a cylindrical portion having a plurality of rotationalchannels 440 formed therein. In this embodiment, the rotational channels440 are helical channels or are slots having a bottom shaped as ahelical surface 442. These help convert axial motion to rotary motion asdescribed below.

The sensor 406 is disposed adjacent the flag portion 436 and isconfigured to detect the position of the rotating insert. The sensor 406communicates with the controller (shown as PCB 330 in FIG. 7) on theconsole 100. When the controller receives signals from the sensor 406that the flag portion 436 is in a particular position, the controllermay control the clamp motor 302 to rotate to release a clamped fluidscassette. In one embodiment, the sensor 406 is an optical sensor and theflag portion 436 includes a flag surface having an anodized portion anda reflective portion. In one example, when the anodized portion isadjacent the sensor 406, the sensor 406 does not send a signal however,when the reflective portion of the flag portion 436 is adjacent thesensor 406, the sensor 406 may send a signal to controller, and thecontroller may operate the clamp motor 302 to release the fluidcassette.

The button body 408 includes a hollow portion 450 that receives the boss431 of the rotating insert 404. The button body 408 also includesrotational channels 451 on an inner surface of the hollow portion 450and includes wings 452 projecting from its outer surface. The buttoncover 410 may provide electrical isolation. In this embodiment, it isdisposed over the button body 408 and includes matching wings 454.

The button cover 410 and button 408 fit within a bore 460 on the bezel152. The wings 454 fit within slots 462 in the bore 460 and preventrotation of the button body 408 and the button cover 410.

Ball bearings 468 are disposed within the rotational channels 442, 451,which together form a helical travel path for the ball bearings 468. Inthis embodiment, additional ball bearings 470 disposed between therotating insert 404 and the support portion 402 provide smooth relativerotation between the two components.

In use, the cassette release arrangement 400 converts linear motion torotational motion via a helical interface formed by the rotationalchannels 440, 451. The sensor 406 detects the rotational motion of theflag portion 436 so that the control circuit can initiate the mechanismto release a cassette. If the system is powered down, the rotationalmotion of the rotating insert 404 brings the driving surface 438 on thefinger portion 434 into contact with the projecting drive pin 308 (FIG.7) on the drive wheel 304 (FIG. 7) and pushes it so that it rotates“over center” and the clamp releases from the mechanical energy storedin the clamping springs. The button 162 is restrained to move only inthe Z direction. The rotating insert 404 is restrained to only rotateabout Z axis. The biasing element 412 (e.g., a spring) extends betweenand connects the extension spring arm 418 and the extension spring arm432 and returns the rotating insert 404 back to its starting positionwhen the button 162 is released, which in turn biases the button 162back to the starting position. While shown in a disconnected form inFIG. 11, the spring 412 extends into and connects the extension springarm 418 and the extension spring arm 432. This also pushes both sets ofball bearings back to their starting positions—this assures that theywill have sufficient travel to provide for rolling.

When the button is pushed, the rotating insert 404 rotates until thesensor 406 detects the rotation, and the controller then operates theclamping motor to release the cassette. However, in the absence ofpower, further pushing of the button 162 moves the rotating insert 404further, causing the driving surface 438 on the finger portion 434 topush the projecting drive pin 308 from its position over-center. Thisalso may cause the rollers 218 to move to a position on the ramps 290,permitting the pent-up potential energy in the system via the springs tocause the clamp bracket assembly to displace and release the cassette.

As further discussed above, in some embodiments, a method forinterfacing a surgical cassette to a surgical console may include (a)receiving a surgical cassette on an orientation element configured toorient the surgical cassette for clamping in a surgical console, (b)detecting the presence of the surgical cassette with a first sensor, (c)engaging the surgical cassette with a plurality of fastening elementsdisposed at adjacent corners of the surgical cassette to evenlydistribute a clamping force and move the fastening elements in a firstdirection, and (d) fixing the surgical cassette in place by moving thefastening elements in a second direction. In some embodiments, receivinga surgical cassette on an orientation element may include receiving thesurgical cassette on a plurality of projecting shelf pins shaped tocorrespond to features of the surgical cassette. In some embodiments,engaging the surgical cassette may further include engaging the surgicalcassette with six fastening elements with a substantially equal clampingforce on each fastening element. In some embodiments, fixing thesurgical cassette in place by moving the fastening elements in a seconddirection may include driving a bracket system along a ramp. In someembodiments, the method may further include maintaining the surgicalcassette on the console with a plurality of retaining arms that engage aperimeter of the surgical cassette.

The methods and systems described herein provide a consistent clampingposition and consistent clamping force, while maintaining simplicity andelegance in design. While the terms up, down, and lateral are usedherein, these terms are merely intended to be used as examples based onthe embodiment shown. It is equally understood that the coordinate framecould be changed to provide different modes of operation.

Persons of ordinary skill in the art will appreciate that theembodiments encompassed by the present disclosure are not limited to theparticular exemplary embodiments described above. In that regard,although illustrative embodiments have been shown and described, a widerange of modification, change, and substitution is contemplated in theforegoing disclosure. It is understood that such variations may be madeto the foregoing without departing from the scope of the presentdisclosure. Accordingly, it is appropriate that the appended claims beconstrued broadly and in a manner consistent with the presentdisclosure.

We claim:
 1. A surgical cassette clamping system comprising: a bracketsystem comprising a fastening element configured to engage a surgicalcassette; a pivot arm pivotably connected to the bracket system at apivot location; and a clamp motor operably connected to the bracketsystem to move the bracket system in a first direction; a biasing systembetween the pivot arm and the bracket system, the biasing systemconnecting to the bracket system at a first connecting location andconnecting to the pivot arm at a second connecting location to maintaina relatively consistent clamping force on the fastening element engagingthe surgical cassette; wherein the bracket system is configured to movein the first direction, and the fastening element of the bracket systemis configured to move in a second direction to secure the surgicalcassette; wherein the bracket system comprises a motion bracket and aclamp bracket, the clamp bracket comprising the fastening element andthe motion bracket comprising the first connecting location.
 2. Thesurgical cassette clamping system of claim 1, wherein as the bracketsystem is moved in the first direction, the fastening element of thebracket system is configured to simultaneously move in the seconddirection to secure the surgical cassette.
 3. The surgical cassetteclamping system of claim 1, wherein the relatively consistent clampingforce is a clamping force that deviates less than about 10% over a pivotrange of about 10 degrees.
 4. The surgical cassette clamping system ofclaim 1, further comprising a clamping spring connecting the clampbracket and the motion bracket.
 5. The surgical cassette clamping systemof claim 1, comprising rollers enabling smooth translation of the motionbracket relative to the clamp bracket.
 6. The surgical cassette clampingsystem of claim 1, comprising a cassette release arrangement configuredto convert linear motion into rotational motion to mechanically releasethe surgical cassette from the surgical cassette clamping system.
 7. Thesurgical cassette clamping system of claim 6, wherein the cassetterelease arrangement comprises a controller and a position detector incommunication with the controller, the controller being configured toelectronically control release of the surgical cassette from thesurgical cassette clamping system.
 8. The surgical cassette clampingsystem of claim 1, further comprising: a faceplate having a first sideand a second side on an opposing side of the faceplate; wherein thebracket system is disposed adjacent the first side of the faceplate, thebracket system comprising at least two connectors.
 9. The surgicalcassette clamping system of claim 1, wherein the biasing system is aspring.
 10. The surgical cassette clamping system of claim 1, whereinthe first direction is perpendicular to the second direction.
 11. Asurgical cassette clamping system comprising: a bracket systemcomprising a fastening element configured to engage a surgical cassette;a pivot arm pivotably connected to the bracket system at a pivotlocation; and a clamp motor operably connected to the bracket system tomove the bracket system in a first direction; a biasing system betweenthe pivot arm and the bracket system, the biasing system connecting tothe bracket system at a first connecting location and connecting to thepivot arm at a second connecting location to maintain a relativelyconsistent clamping force on the fastening element engaging the surgicalcassette; wherein the bracket system is configured to move in the firstdirection, and the fastening element of the bracket system is configuredto move in a second direction to secure the surgical cassette; whereinthe pivot arm comprises a roller spaced from the pivot location.
 12. Thesurgical cassette clamping system of claim 11, further comprising a rampdisposed relative to the roller, the ramp displacing the bracket systemin a direction to clamp the surgical cassette with the fasteningelements, the ramp forcing the pivot arm to pivot about the pivotlocation as the bracket system moves.
 13. The surgical cassette clampingsystem of claim 11, wherein as the bracket system is moved in the firstdirection, the fastening element of the bracket system is configured tosimultaneously move in the second direction to secure the surgicalcassette.
 14. The surgical cassette clamping system of claim 11, whereinthe relatively consistent clamping force is a clamping force thatdeviates less than about 10% over a pivot range of about 10 degrees. 15.The surgical cassette clamping system of claim 11, wherein the firstdirection is perpendicular to the second direction.
 16. A surgicalcassette clamping system comprising: a bracket system comprising afastening element configured to engage a surgical cassette; a pivot armpivotably connected to the bracket system at a pivot location; and aclamp motor operably connected to the bracket system to move the bracketsystem in a first direction; a biasing system between the pivot arm andthe bracket system, the biasing system connecting to the bracket systemat a first connecting location and connecting to the pivot arm at asecond connecting location to maintain a relatively consistent clampingforce on the fastening element engaging the surgical cassette; whereinthe bracket system is configured to move in the first direction, and thefastening element of the bracket system is configured to move in asecond direction to secure the surgical cassette; wherein the surgicalcassette clamping system further comprises a faceplate having a firstside and a second side on an opposing side of the faceplate; wherein thebracket system is disposed adjacent the first side of the faceplate, thebracket system comprising at least two connectors; wherein the clampmotor is disposed adjacent the faceplate and fixed relative to thefaceplate; and wherein the pivot arm is one of a plurality of pivot armspivotably connected to the bracket system via the at least twoconnectors and extending adjacent the second side of the faceplate,wherein the plurality of pivot arms comprise rollers.
 17. The surgicalcassette clamping system of claim 16, wherein the second side of thefaceplate comprises ramps; wherein as the bracket system moves in thefirst direction relative to the faceplate, the rollers ride along theramps such that the bracket system simultaneously moves in the seconddirection toward the first side of the faceplate.
 18. The surgicalcassette clamping system of claim 16, wherein as the bracket system ismoved in the first direction, the fastening element of the bracketsystem is configured to simultaneously move in the second direction tosecure the surgical cassette.
 19. The surgical cassette clamping systemof claim 16, wherein the relatively consistent clamping force is aclamping force that deviates less than about 10% over a pivot range ofabout 10 degrees.
 20. The surgical cassette clamping system of claim 16,wherein the first direction is perpendicular to the second direction.